In vivo cytogenetic screening methods for mutagens, with special reference to the micronucleus test

Abstract

It has been claimed that the micronucleus test (MNT) is a simple and practical in vivo cytogenetic screening method for mutagens. To evaluate the MNT as an initial screening method, mice and Chinese hamsters were treated in vivo with triethylene melamine (0.016, 0.032, 0.062, 0.125, or 0.25 mg/kg), azathioprine (50, 200, or 500 mg/kg), colchicine (0.625, 1.25, or 2.5 mg/kg) or caffeine (100, 200, or 250 mg/kg). The treated animals were examined by means of the MNT, chromosome analysis (CA) and sister chromatid exchange (SCE) scoring. For the MNT and CA, each dose level was applied twice to 3–4 animals with an interval of 24 h. For the SCE test, the animals received a treatment with 5-bromodeoxyuridine (BUDR) and 5-fluorodeoxyuridine (FUDR), during which time the test compounds were administered once.